Under the cap? You need to check again, they have $81m committed to players next year not including Draymonds contract. Lets say they bring back Speights (the only team option, $3.8m) and Draymond gets $9m (and I wouldn't be surprised if he got more), that puts them at $90m.
Assuming the tax starts around $80m, they'd be liable for $16.25m in tax, meaning their roster costs them $106m. Draymond Green effectively becomes a $26m player which is crazy, they will either let him go or trade Lee/Iggy so they get back under the tax.